Statement  for  the  110^{th  Congress  (1st  Session)  in  support  of  H.R.  249  A  BILL  IN  THE  HOUSE  OF  REPRESENTATIVES}

House  Committee  on  Natural  Resources  

(Introduced  January  5,  2007)  

(Bill  updates  at  The  Library  of  Congress  Website:  http://thomas.loc.gov/)    

By  Jay  F.  Kirkpatrick,  Ph.D.  and  Patricia  M.  Fazio,  Ph.D.*  

Are  wild  horses  truly  "wild,"  as  an  indigenous  species  in  North  America,  or  are  they  "feral  weeds"  –  barnyard  escapees,  far  removed  genetically  from  their  prehistoric  ancestors?  The  question  at  hand  is,  therefore,  whether  or  not  modern  horses,  Equus  caballus,  should  be  considered  native  wildlife.    

The  genus  Equus,  which  includes  modern  horses,  zebras,  and  asses,  is  the  only  surviving  genus  in  a  once  diverse  family  of  horses  that  included  27  genera.   The  precise  date  of  origin  for  the  genus  Equus  is  unknown,  but  evidence  documents  the  dispersal  of  Equus  from  North  America  to  Eurasia  approximately  2‐3  million  years  ago  and  a  possible  origin  at  about  3.4‐3.9  million  years  ago.  Following  this  original  emigration,  several  extinctions  occurred  in  North  America,  with  additional  migrations  to  Asia  (presumably  across  the  Bering  Land  Bridge),  and  return  migrations  back  to  North  America,  over  time.  The  last  North  American  extinction  occurred  between  13,000  and  11,000  years  ago.1  Had  it  not  been  for  previous  westward  migration,  over  the  land  bridge,  into  northwestern  Russia  (Siberia)  and  Asia,  the  horse  would  have  faced  complete  extinction.  However,  Equus  survived  and  spread  to  all  continents  of  the  globe,  except  Australia  and  Antarctica.   

In  1493,  on  Columbus’  second  voyage  to  the  Americas,  Spanish  horses,  representing  E.  caballus,  were  brought  back  to  North  America,  first  in  the  Virgin  Islands,  and,  in  1519,  they  were  reintroduced  on  the  continent,  in  modern‐day   

1 "Horse Evolution" by Kathleen Hunt from http://www.talkorigins.org/faqs/horses/horse_evol.html (To access this Website, search by title and author); Bruce J. MacFadden, Fossil Horses: Systematics, Paleobiology, and Evolution of the Family Equidae (New York: Cambridge University Press, 1992), p. 205.

Patricia Mabee Fazio, "The Fight to Save a Memory: Creation of the Pryor Mountain Wild Horse Range (1968) and Evolving Federal Wild Horse Protection through 1971," doctoral dissertation, Texas A&M University, College Station, 1995, p. 21.  

 Ann Forstén, 1992. Mitochondrial-DNA timetable and the evolution of Equus: Comparison of molecular and paleontological evidence. Ann. Zool. Fennici 28: 301-309.

Mexico,  from  where  they  radiated  throughout  the  American  Great  Plains,  after  escape  from  their  owners.   

Critics  of  the  idea  that  the  North  American  wild  horse  is  a  native  animal,  using  only  paleontological  data,  assert  that  the  species,  E.  caballus  (or  the  caballoid  horse),  which  was  introduced  in  1519,  was  a  different  species  from  that  which  disappeared  13,000  to  11,000  years  before.  Herein  lies  the  crux  of  the  debate.  However,  the  relatively  new  (27‐year‐old)  field  of  molecular  biology,  using  mitochondrial‐DNA  analysis,  has  recently  found  that  the  modern  or  caballine  horse,  E.  caballus,  is  genetically  equivalent  to  E.  lambei,  a  horse,  according  to  fossil  records,  that  represented  the  most  recent  Equus  species  in  North  America  prior  to  extinction.  Not  only  is  E.  caballus  genetically  equivalent  to  E.  lambei,  but  no  evidence  exists  for  the  origin  of  E.  caballus  anywhere  except  North  America.

According  to  the  work  of  Uppsala  University  researcher  Ann  Forstén,  of  the  Department  of  Evolutionary  Biology,  the  date  of  origin,  based  on  mutation  rates  for  mitochondrial‐DNA,  for  E.  caballus,  is  set  at  approximately  1.7  million  years  ago  in  North  America.  Now  the  debate  becomes  one  of  whether  the  older  paleontological  fossil  data  or  the  modern  molecular  biology  data  more  accuratey  provide  a  picture  of  horse  evolution.  The  older  taxonomic  methodologies  looked  at  physical  form  for  classifying  animals  and  plants,  relying  on  visual  observations  of  physical  characteristics.  While  earlier  taxonomists  tried  to  deal  with  the  subjectivity  of  choosing  characters  they  felt  would  adequately  describe,  and  thus  group,  genera  and  species,  these  observations  were  lacking  in  precision.   

Reclassifications  are  now  taking  place,  based  on  the  power  and  objectivity  of  molecular  biology.  If  one  considers  primate  evolution,  for  example,  the  molecular  biologists  have  provided  us  with  a  completely  different  evolutionary  pathway  for  humans,  and  they  have  described  entirely  different  relationships  with  other  primates.  None  of  this  would  have  been  possible  prior  to  the  methodologies  now  available  through  mitochondrial‐DNA  analysis.  

Carles  Vilà,  also  of  the  Department  of  Evolutionary  Biology  at  Uppsala  University,  has  corroborated  Forstén’s  work.  Vilà  et  al  have  shown  that  the  origin  of  domestic  horse  lineages  was  extremely  widespread,  over  time  and  geography,  

 Carles Vilà, Jennifer A. Leonard, Anders Götherström, Stefan Marklund, Kaj Sandberg, Kerstin Lidén, Robert K. Wayne, Hans Ellegren. 2001. Widespread origins of domestic horse lineages. Science 291: 474-477.

 Hofreiter, Michael; Serre, David; Poinar, Hendrik N.; Kuch, Melanie; Pääbo, Svante. 2001. Ancient DNA. Nature Reviews Genetics. 2(5), 353-359.

 James Dean Feist and Dale R. McCullough. 1976. Behavior patterns and communication in feral horses. Z. Tierpsychol. 41: 367.

and  supports  the  existence  of  the  caballoid  horse  in  North  American  before  its  disappearance.   

Finally,  the  work  of  Hofreiter  et  al,    examining  the  genetics  of  the  so‐called  E.  lambei  from  the  permafrost  of  Alaska,  found  that  the  variation  was  within  that  of  modern  horses,  which  translates  into  E.  lambei  actually  being  E.  caballus,  genetically.  The  molecular  biology  evidence  is  incontrovertible  and  indisputable.   

The  fact  that  horses  were  domesticated  before  they  were  reintroduced  matters  little  from  a  biological  viewpoint.  They  are  the  same  species  that  originated  here,  and  whether  or  not  they  were  domesticated  is  quite  irrelevant.  Domestication  altered  little  biology,  and  we  can